1) CMR nếu USCLN(m,n)=1 thì Z_m x Z_n đẳng cấu Z_{m*n}.  Ở đây m,n là các số tự nhiên.
2) Giả  sử p là số nguyên tố. CMR Z_{p*p} không đẳng cấu với nhóm Z_p x Z_p.
3) Giả sử G là nhóm đơn giản (simple) hữu hạn hoặc vô hạn. CMR bậc của G là số nguyên tố.

Tìm số 8

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tìm chữ o

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điền vào chỗ trống:

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trả lời đi

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